Remove file named .d created in the source directory

I59b20c931ee3e5a8d35eb30da4148691c5095502 accidentally wrote depsfiles
to a file called .d in the top level of the source tree, remove them.

Bug: 119412419
Test: m
Change-Id: Iaf71a64a7ee4aa39084423dfd16aa934613ba158
diff --git a/CleanSpec.mk b/CleanSpec.mk
index 45ca7c1..b06a87b 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -527,6 +527,7 @@
 
 # Remove incorrectly created directories in the source tree
 $(call add-clean-step, find system/app system/priv-app system/framework system_other -depth -type d -print0 | xargs -0 rmdir)
+$(call add-clean-step, rm -f .d)
 
 # ************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST